I need to create plugin for NSIS installer using Delphi. I can't use C/C++, because some of the code is already Delphi-written in secondary project. I used manual - NSIS\Examples\Plugin\nsis.pas. Can someone explain me this part of implementation code?

For example, I call this function: NSIS_Call('MyBestFunctionInScript').
But, "MyBestFunctionInScript" (value of "codeoffset") will be converted at 0 always (why StrToIntDef?). Maybe need to remove StrToIntDef on other function?

In C-example I find this interface (maybe it's normal working convertion string function name at codeoffset):